docs: def get_bcache_fs():
      """Return all cache sets
      """
      cachesetroot = "{}/fs/bcache".format(SYSFS)
      try:
          dirs = os.listdir(cachesetroot)
      except OSError:
          log("No bcache fs found")
          return []
      cacheset = set([Bcache('{}/{}'.format(cachesetroot, d)) for d in dirs if not d.startswith('register')])
      return cacheset